Reaction-transmitting mechanism adapted for brake booster motor use



Apnl 19, 1966 G. T. RANDOL 3,246,578

REACTION-TRANSMITTING MECHANISM ADAPTED FOR BRAKE BOOSTER MOTOR USEOriginal Filed Sept. 21, 1962 United States Patent 3 246 573 REAUTEUNTRANMl'lTlNG MECHANISM ADAPTED FGR BRAKE BOOSTER MOTGR This applicationis a division of my copending application Serial No. 225,427 filedSeptember 21, 1962 now issued to Patent No. 3,209,657 dated October 5,1965.

The invention relates to novel reaction-transmitting mechanism disclosedin said earlier filed application and illustrated by way of example, inoperative association with my novel brake booster motor having a powermember operated by a pressure differential and wherein said mechanism isoperatively embodied between said power member and the work outputelement movable in part thereby with portions of said mechanism beingresponsive to initial operator-actuation eifective to subject said workelement to a predetermined resistance to movement for conditioning saidmechanism to transmit a portion of the reaction from said work elementto the operator upon operative energization of said power memberreaching sufficient magnitude in cooperation with operator-actuationcontrol thereof to overcome said predetermined resistance (work-load) toadditionally move said work element.

Workers in the art to which the present invention relates, haveheretofore proposed various pressure-sensing devices adapted fortransmitting to the operator through the medium, for example, of a pedalan awareness of the energized status of booster motors employed toassist in operating the conventional hydraulic brake system onautomotive vehicles and the like, but none of such proposals provides areaction-transmitting system in which a plurality of radially-arrangedcomposite levers characterized by lever-action is combined withresiliency of a rubber block or the like embodied between at least twospaced segmental portions comprising each of the levers, said segmentalportions being characterized by limited relative movement toward eachother from normal position to deform the interposed block to produce inconjunction with the aforesaid lever-action the means .for transmittinga portion of the reaction from said work element to the operator.

The primary objective, therefore, of the present invention is to providea reaction mechanism or system of the latter type wherein lever-actionis combined in a novel manner with a pliant element disposed in each ofa plurality of radially arranged composite levers to produce aprogressively increasing resistance to movement of an operator-operatedmember (brake-pedal) and the booster power member as a function ofreaction from the workperforming element adapted to operate, forexample, the master brake cylinder (not shown) whereby the operator isprovided with a highly desirable pedal feel to enable him to predictablyregulate the degree of braking force as required.

Another object of the invention seeks to provide novel mechanism forreaction-transmission from a work-load to an operator-operated membercapable of controlling a power force whereby the reaction forcetransmittable to the operator member is a factor of the blending ofmechanical leverage and a resilient element embodied directly in saidmechanical leverage, to provide a progressively increasing resistance tomovement of the operator member upon operative energization of saidpower force to assist in the movement and pressure exerted on aforceapplying element eiiective on said work-load.

3,246,573 Patented Apr. 19, 1966 Additional objects, advantages andfeatures of the invention will become apparent from the followingdetailed description considered in connection with the accompanyingdrawing wherein a preferred embodiment of the invention is exemplarilyillustrated as follows:

FIGURE 1 depicts my novel reaction-transmitting mechanism embodied in abooster brake motor controllable in part by an operator-operated pedal,said mech anism being shown in normal relaxed disposition;

FIGURE 2 is a transverse section taken along the line 2-2 of FIGURE 1showing further particulars of the reaction mechanism; and

FIGURE 3 is a fragmentary sectional view taken on an enlarged scale fromFIGURE 1 showing one of the reaction levers per se in assembled statusprior to installation in the booster motor.

Referring now to the drawing, my novel and improvedreaction-transmitting mechanism is shown in operative association with apower unit herein disclosed in the form of a pressure differentialoperated booster motor generally designated BM and shown fragmentarilyby FIG- URE 1, said motor comprising a cup-shaped power cylinder whichutilizes a detachable cup-shaped member 12 to close its open end, and apower assembly illustrated herein as a power-piston PP reciprocablymounted for movement within said power cylinder, and which serves todivide said cylinder interior into opposing fluid chambers 14, 15, saidchamber 14 being characterized by being subjected to a variable pressure(air-vacuum) and the other chamber 15 being continuously charged with anegative pressure (vacuum) with both of said chambers being normallybalanced at negative pressure level when the power-piston PP is innormal position as shown in PiGURE 1, thus the present booster motor BMis commercially known as the vacuum-suspended type as distinguished fromthe air-suspended type characterized by equivalent atmospheric pressureconditions present in both of said chambers when the motor isde-energized.

The aforesaid differential pressure is created by admitting air atatmospheric pressure level into chamber 14 under control of a follow-upcontrol valve mechanism generally designated CV which in operation underinfluence in part of an operator-operated member herein illustrated inthe form of the conventional suspended-type brake-pedal P, activates avalve actuator VA herein disclosed as a valve-carrying unit of compositeconstruction and characterized by rectilinear movement. The valveactuator comprises an inner valve element 41 and a portion 42 projectingforwardly therefrom and a tubular portion 43 which projects rearwardthrough a central opening in the closure member 12 for connection to thebrakepedal P.

The power-piston PP comprises a preferably circular master thrust plate108 which backs a juxtaposed first thrust plate 109 of annularconfiguration, and a secondary support and sealing plate 110characterized by a centrally extruded e-mbossment 114 with a flangedcentral circular opening 115, to produce an enclosure (chamber) 118 withits rear open end closed by said master plate. These three plates areassembled as shown in FIGURE 1 by means of a plurality of rivets 122 orotherwise, to produce said power assembly.

An outer valve member (sleeve) 124 is connected to move as a unit withthe power-piston PP by means of a valve cage 143 whereby operator forceapplied to the valve actuator VA effects simultaneous rectilinearmovement of the inner valve element 41 relative to the outer valvemember, and thereby producing in operative association with the outervalve member 124 moving as a unit with said power-piston PP, therequisite follow-up operation of control by said control valve CV toconnect the power cylinder chamber to atmosphere to create a pressuredifferential across said power-piston to operatively energize the same.

The power cylinder chamber 15 continuously communicates with a vacuumsource (not shown) via a conduit 135, and an annular vacuum chamber 127formed in the outer valve member 124 as shown in FIGURE 1. This lattermember is also provided with a pair of diametrically opposed air-vacuumslots 129 which maintains communication between the power cyilnderchamber 14 and said inner valve element. Spaced forwardly from theseslots is an annular end Wall 131 defining the forward end of said valvechamber 127. The inner valve element is provided with an annular workingland 130 and a pair of diametrically opposed air-slots 133 whichcooperate with said end wall and slots 129, respectively, to selectivelyconnect said vacuum chamber 127 to the power cylinder chamber 14 and toisolate the latter two chambers in synchronism with the slots 129 andairslots 133 being placed in and out of registry, respectively, toproduce the aforesaid pressure differential in said power cylinderchambers 14, 15 when said valve chamber 127 is isolated and said slots129, 133 in communication with each other for induction of atmosphericpressure into the power cylinder chamber 14 under follow-up control ofsaid control valve CV as is understood.

The booster work-performing element (push-rod) 18 operates the mastercylinder piston (not shown), and the opposite rear end portion of saidpush-rod is formed with an enlarged diameter cylindrical portion 156fitted with an annular packing 158 and which slidably interfits theaforesaid opening 115 in airtight sealed relation to isolate the chamber118 from chamber 15 as shown in FIG- URE 1. This enlarged portion of thepush-rod terminates in a narrow extension 159 of substantiallyrectangular cross section which projects into the bifurcated forward end42 defining a horizontal cross-slot 163. The forward portion 42 alsoprojects through and is slidably supported by a complemental aperture164 in a preferably plastic bearing element 165 incorporated in acentral opening 166 formed in the master plate 108 of the powerpiston PPas shown in FIGURE 1. It should be importantly noted here that thebottom of the cross-slot 163 is normally spaced at 167 from theconfronting end of the narrow extension 159 to provide the requiredrelative operating movement between the valve actuator VA and outervalve sleeve 124 for follow-up operation of the aforesaid control valveCV between its off" and wide open operating positions of control.

When the bottom of the cross-slot 163 engages the end of the push-rodextension 159, operator force may be applied directly to the boosterpush-rod 18 to operate the master brake cylinder (not shown)straight-through in cooperation with or independently of boosterpower-assist. Movement of the valve actuator VA under operatoractuationis transmitted to the booster push-rod 18 through my novelreaction-transmitting mechanism (device) generally designated RL andwhich comprises: a pressure plate 211 centrally apertured at 212 toreceive the reduced ends of the bifurcated portion 42 of the valveactuator VA, and which is stabilized on the portion 42 by shoulders 181to have unitary movement with said valve actuator. The lower and upperends of this plate terminate in horizontal forwardly projecting flanges213, 214, respectively, with each flange notched at 215 to provide apressure point generally designated 216, for the inner ends of thecomposite reaction levers of springy loopshaped construction andgenerally designated 217.

Each of the reaction levers 217 is formed with an outwardly extendingradial segment (arm) 218 normally parallel to the left side of themaster thrust plate 108 with an arcuate offset portion 219 projectingfrom the outer end portion toward and in contiguous relationship to saidthrust plate. The outer end portion above said offset portion takes theform of a springy arch 221 terminating in an inwardly extending radialsegment (arm) 222 preferably spaced at an angle from the confrontingportion of the outwardly extending segment. The inner end of the segment222 terminates in a substantially horizontal narrower segment (arm) 223with the free end thereof spaced from the outwardly extending segment toprovide normally a substantially triangular opening 224 adapted toreceive a resilient block of rubber 225 of the same generalconfiguration.

A channel 226 is provided in the inner end surface coextensive with thelength of the rubber block and which receives the narrow segment 223 tostabilize the rubber blocks within their respective enclosures definedby the configuration of the radial segments and connecting springy arch221 comprising each of said levers as above described, said channel alsoenabling the inwardly extending segment 222 and horizontal segment 223to have yielding relative movement toward the outwardly extendingsegment 218 when the rubber olocks under compression induced by thelevers under reactive force from the master brake cylinder (not shown).

The juncture of the inwardly extending and horizontal segments 222, 223,respectively, pushes against opposite ends of a fulcrum member 227mounted on the booster push-rod 18 to bear against opposed shouldersdefining the juncture of the cylindrical element 156 and rectangularextension 159 projecting coaxially therefrom. The left side of member227 normally lies in contact with the inner confronting face of theembossment 114 on the secondary plate as shown, and the taperedcylindrical wall of the embossment overlying the outer ends of thelevers 217, is depressed parallelly to the axis of the booster push-rodto lie in close adjacency to the arched ends aforesaid to preventfortuitous radial displacement of the two reaction levers 217, thusstabilizing them in operating positions. The normal angular relationshipof the inwardly extending and outwardly extending segments of the levers217 is demonstrated by FIGURE 3 wherein said segment 222 is angularlyspaced from the left side of the rubber block, but when the levers areinstalled as shown in FIGURE 1, segments 218, 222 are biased toward eachother to not only place some tension in the levers proper as requiredfor the reactive transmission effect desired but also preferably to aminute degree in the rubber blocks. Thus, when the valve actuator VAmoves to the left from normal position of FIGURE 1, immediate resistanceis encountered to pedal movement which builds up progressively as thebooster power-piston PP becomes increasingly operatively energized.

In operation, with the parts in relative positions as shown in FIGURE 1,initial movement of the valve actuator VA under operator-actuation,pushes on the inner ends of the reaction levers 217 producing a tendencyfor the outwardly extending segments to rotate clockwise on theirarcuate offset portions abutting the forward face of the master thrustplate 108, and at the same time the power-piston PP under influence ofpressure differential created in the manner aforesaid acts through saidarcuate offsets to transmit movement via the inwardly extending segments222 to the fulcrum member 227 thence to the booster push-rod 18 to movethe master cylinder piston (not shown) for brake operation. Thiscombined action of operator force and power force reduces the size andmodifies the shape of the opening in which the rubber blocks,respectively, are disposed thus causing the rubber blocks tocorrespondingly deform according to their inherent consistency to resistdeformation in relation to the degree of pressure acting thereon as afunction of limited movement of the radial segments toward each other,and thereby supplementing the resistance produced by the increasingbuildup of tension in the levers under reaction from the master brakecylinder (not shown).

The two diametrically opposed areas 228, 229 on the master thrust plate108 in contact with the arcuate offset portions on the levers 217,define the outer pressure points while the inner ends of the levers areacted on by the bottoms of the notches in the lower and upper flanges213, 214 which serve as the inner pressure points for the levers 217 andwhich are charactererized by both resiliency, that is, capable ofyielding, and mechanical lever-action, the latter operatingcharacteristic effecting the deformation of the rubber blocks to producethe combined resilient resistance to pedal movement as a measure of thebrakeapplying operation under joint influence of operator and powerforces as is understood.

It should be manifest from the foregoing illustration and description ofmy invention that I have produced a novel lever-typereaction-transmitting mechanism for booster motors which providesspecial advantages, particularly in the provision of what may be termeda soft pedal feel without sacrificing predictable control over theoperative energization of the booster motor. The reaction-lever deviceRL provides a wide range of variables in leverage ratio resiliency as aproduct of the combination of mechanical leverage with a resilientelement, to enable the operator (driver) to sense the degree of brakeapplication, such structural variations in the reaction device beingincorporable in the disclosed booster motor or other booster designsaccording to the requirements of the particular installation and driverschoice with respect to pedal feel desired.

A preferred embodiment of the invention has been illustrated anddescribed. However, it is obvious that modifications, changes andvariations may be made by workers in the art to which the inventionrelates with out departing from the proper scope or fair meaning of theterms of the subjoined claims.

Having thus described my invention, I claim:

1. In reaction-transmitting mechanism adapted for use in cooperationwith a work-performing element to transmit reaction therefrom to a powermember operative to exert the major portion of pressure on said element,and to a personally-actuatable member effective to control operation ofsaid power member and simultaneously exert the balance of pressure onsaid element, comprising a plurality of radially extending loop-shapedspring levers, each having a radially extending segment with an arcuateportion offset at its outer end into engagement with said power member,and the inner end in engagement with an extension coaxially projectingfrom said personal member, another radially extending segment normallyspaced from said first-defined segment, and which is interconnected withan arched portion defining the extreme outer ends of both radialsegments and including a horizontal segment projecting from the innerend of the other radial segment toward said first-defined segment inspaced relationship thereto, and a resilient block confined in the spacedefined by said segments in substantially the same configuration as thespace obtaining within said segments in operating disposition; and afulcrum member coaxially mounted on said work element for movement as aunit therewith, with its peripheral portion engaging the inner end ofthe other radial segment whereby forces transmitted by said personalmember and power member to said first-defined segment are progressivelyresisted as a function of the inherent opposition of the levers to yieldsupplemented by resistance of said block against compressive deformationby said radial segments in response to reaction transmitted by said workelement via said fulcrum member when said power and personal members areoperatively cooperating.

2. In reaction-transmitting mechanism adapated for use in cooperationwith a work-performing element to transmit reaction therefrom to a powermember operative to activate in part said work element, and to apersonally-operable member effective to control and coopcrate with saidpower member to complete activation of said work element, comprising amovable member, a pressure area on said power member, another pressurearea on said movable member radially spaced from said first-definedpressure area; a fulcrum area provided on said work element intermediatesaid pressure areas aforesaid in offset relation thereto; a plurality ofradially arranged composite levers, each of said levers beingcharacterized by resiliency and comprising a radially extending segmentand an angularly spaced segment depending from and interconnected by anarch segment with the outer end of said first defined segment of saidlever, said depending segment terminating in a horizontal segment normalto the inner end of said depending segment and projecting toward saidfirst-defined segment in spaced relationship to the latter segment; ablock characterized by resiliency and disposed in the opening producedby said lever segments; an arcuate offset in the outer end of saidfirst-defined segment to serve as a pivotal point for said lever on saidpressure area of said power member, the inner end of said first-definedsegment being engageable by the pressure area on said movable member;and means for transmitting operator force from said personal member tosaid movable member to reduce and modify the opening defined by saidlever segments and thereby deforming said block accordingly to providereaction from said work element via said fulcrum area in engagement withthe lower end of said depending segment, thus providing the operatorwith progressively increasing resistance to sense the amount of workbeing performed by said work element under joint influence of said powerand personal members upon said power member becoming operativelyenergized.

3. In reaction-transmitting mechanism adapted for use in cooperationwith a work-performing element to transmit reaction therefrom when actedon jointly by a pair of cooperating actuatable members, with one of saidmembers being effective to control the other member, comprising apressure area operatively associated with one of said members; anotherpressure area operatively associated with the other of said members andradially spaced from the first-defined pressure area; a fulcrum areaprovided on said work element intermediate said two pressure areasaforesaid in offset relationship thereto; a plurality of reaction-leversarranged in radially extended relationship from an axis common to bothof said members, each of said reaction-levers comprising a resilientsegment formed with an elongated radial segment having its extremescontiguous to said pressure areas, respectively, an inwardly extendingradial segment spaced from the outer end portion of said first-definedsegment, and including a horizontal segment normal to the inner end ofsaid inwardly extending segment and projecting toward the first-definedsegment in spaced relationship to the latter segment, to produce anopening defined by said segments; a resilient block of substantially thesame perimetrical configuration as said opening; a longitudinal channeltraversing the lower end of said block for reception of said horizontalsegment; and a pressure point at the vertex of said inwardly extendingand horizontal segments contiguous to the pressure area on said workelement to effect initial tensioning of said radial and upstandingsegments and to simultaneously modify the normal size of said openingdefined by said segments whereby said block is deformed accordinglyunder compressive action to conform to the modified status of saidopening to supplement the tension in said reaction-levers to jointlytransmit a progressively augmented reactive resistance to saidactuatable members; and an operatoroperated member adapted to actuateone of said actuatable members relatively to said other member totension said reaction-levers and thereby deforming said block confinedtherein for joint reaction transmission from said work element.

4. In reaction-transmitting mechanism adapted for use in cooperationwith a work-performing element to transmit reaction therefrom to a pairof cooperating actuatable members acting through said mechanism on saidwork element, with one of said members being adapted to control theother member, comprising a resilient reaction-transmitting member ofloop-shaped configuration defined by a pair of spaced segments connectedat one end and open at their opposite ends, said segments beingcharacterized by limited relative movement toward each other from normalposition; a fulcrum provided on said work element on which one of saidsegments is rockable; a pair of spaced pressure areas associated withsaid actuatable members, respectively, on which the extremes of theother segment are rockable, respectively; a resilient block disposed inthe space between said segments and which is deformable undercompressive force applied by said segments when moved toward each otherunder actuation of said actuatable members to modulate the spacenormally obtaining between said segments thereby producing aprogressively augmented reaction resistance from said work elementagainst said actuatable members.

5. A reaction-transmitting mechanism constructed in accordance withclaim 4 in which said block and reaction members are normally placedunder minimal tension simultaneously when installed to provide immediateinitial resistance to actuation of said one actuatable member forpredictable control of said other actuatable member to intensify thereactive force.

6. In reaction-transmitting mechanism having operative interpositionwith respect to a pair of actuatable members and a work output element,with one of said members being adapted to control the other member,comprising a composite lever having a pair of spaced arms connected formovement toward each other to reduce the space normally obtainingtherebetween, and which is adapted to provide mechanical leveragebetween said work element and pair of members, and having an interposedcooperative resilient block occupying the space normally obtainingbetween said pair of arms, and deformable upon movement of the lattertoward each other to supplement the springy action of said lever toapply a progressively increasing impositive reaction from said workelement on said actuatable members upon actuation of said other member.

7. In reaction-transmitting mechanism having operative interpositionwith respect to a pair of actuatable members and a work output element,with one of said members being adapted to control the other member,

comprising a lever having a pair of spaced arms yieldably connected formovement toward each other, and which is adapted to provide a yieldingmechanical leverage between said work element and said pair of membersto apply a progressively increasing unproportionate reaction from saidwork element on both of said actuatable members upon actuation of saidother member under control of the one actuatable member.

8. In reaction-transmitting mechanism adapted for use in cooperationwith a work-performing element to transmit reaction therefrom to a powermember operative to exert the major portion of pressure on said element,and to a personally-actuatable member and simultaneously exert thebalance of pressure on said element, comprising a plurality of radiallyextending looped-shaped springy levers, each having a radially extendingsegment with an arcuate portion offset at its outer end into engagementwith said power member, and the inner end in engagement with anextension coaxially projecting from said personal member, an angularlyinwardly extending radial segment interconnected with an arched portiondefining the extreme outer ends of both radial segments and including ahorizontal segment projecting from the inner end of said angularlyextending segment spaced from said first-defined segment; and a fulcrummember c0- axially mounted on said work element for movement as a unittherewith, with its peripheral portion engaging the inner end of theangularly extending segment whereby forces transmitted by said personalmember and power member to said first-defined segment are progressivelyresisted as a function of the inherent opposition of said levers toyield in response to reaction transmitted by said work element via saidfulcrum member when said power and personal members are operativelycooperating.

References Cited by the Examiner UNITED STATES PATENTS 2,894,490 7/1959Ingres 91369 2,900,963 8/1959 Ayers 91-369 3,026,853 3/1962 Stelzer9l-369 SAMUEL LEVINE, Primary Examiner.

EDGAR W. GEOGHEGAN, Examiner.

P. E. MASLOUSKY, Assistant Examiner.

1. IN REACTION-TRANSMITTING MECHANISM ADAPTED FOR USE IN COOPERATIONWITH A WORK-PERFORMING ELEMENT TO TRANSMIT REACTION THEREFROM TO A POWERMEMBER OPERATIVE TO EXERT THE MAJOR PORTION OF PRESSURE ON SAID ELEMENT,AND TO A PERSONALLY-ACTUATABLE MEMBER EFFECTIVE TO CONTROL OPERATION OFSAID POWER MEMBER AND SIMULTANEOUSLY EXERT THE BALANCE OF PRESSURE ONSAID ELEMENT, COMPRISING A PLURALITY OF RADIALLY EXTENDING LOOP-SHAPEDSPRING LEVERS, EACH HAVING A RADIALLY EXTENDING SEGMENT WITH AN ARCUATEPORTION OFFSET AT ITS OUTER END INTO ENGAGEMENT WITH SAID POWER MEMBER,AND THE INNER END IN ENGAGEMENT WITH AN EXTENSION COAXIALLY PROJECTINGFROM SAID PERSONAL MEMBER, ANOTHER RADIALLY EXTENDING SEGMENT NORMALLYSPACED FROM SAID FIRST-DEFINED SEGMENT, AND WHICH IS INTERCONNECTED WITHAWN ARCHED PORTION DEFINING THE EXTREME OUTER ENDS OF BOTH RADIALSEGMENTS AND INCLUDING A HORIZONTAL SEGMENT PROJECTING FROM THE INNEREND OF THE OTHER RADIAL SEGMENT TOWARD SAID FIRST-DEFINED SEGMENT INSPACED RE-